Department of Physics, Unit Catalogue 2007/08 |
PH30023 Electromagnetism |
| Credits: 6 |
| Level: Honours |
| Semester: 2 |
| Assessment: CW 20%, EX 80% |
| Requisites: |
| Before taking this unit you must take PH20014 and take PH20020 and in taking this unit you cannot take PH40068 |
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Aims: The aims of this unit are to develop a full formal vectorial description of electric, magnetic and electromagnetic fields in infinite materials and at boundaries between materials, to derive some individual solutions and to make use of them in a few important applications.
Learning Outcomes: After taking this unit the student should be able to: * manipulate full vectorial versions of Maxwell's equations in static and time-varying cases * analyse in detail the propagation of vectorial plane waves in vacuum and in various materials (e.g. lossy dielectrics, metals and plasmas) * derive the origins of polarisation and magnetisation in materials * match electric and magnetic fields at boundaries between materials and explain the origins of Brewster's angle, total internal reflection and tunnelling * calculate the energy density in static and time-varying fields * calculate and make use of the electromagnetic Poynting vector * use static and time-varying scalar and vector potentials to calculate electric, magnetic and electromagnetic fields * outline the basic features of electric and magnetic dipoles * analyse the modes of rectangular metallic waveguides (cut-off, total number of modes, impedance, power flow) * describe some simple antennas and analyse their basic characteristics using magnetic vector potentials. Skills: Numeracy T/F A, Problem Solving T/F A. Content: Mathematical review: vector calculus; div, grad, curl; divergence and Stokes' theorem. Maxwell's equations: Differential form of "static" Maxwell equations from Gauss, Biot-Savart and Ampere Laws. Time variations; Faraday's Law, the continuity equation and vacuum displacement current. Solutions in infinite vacuum: The wave equation. Plane wave solutions and properties; polarisation, impedance. Electromagnetic energy. Poynting's theorem. Radiation pressure. Solutions in infinite materials: Concepts of linearity, isotropy and homogeneity. Characterisation of materials in terms of macroscopic parameters. Dipoles, susceptibility and polarisation / magnetisation vectors fields. Capacitors. The modified wave equation; solution in conductors, dielectrics, lossy media and plasma. Boundaries between media: The general electromagnetic boundary conditions. Plane waves at a planar boundary; general angle of incidence (Fresnel equations). Brewster and critical angles. Coefficients of transmission and reflection at normal incidence. Radiation: Electromagnetic potentials; retarded potentials; near and far fields; radiation from a Hertzian dipole; simple antennas and antenna arrays. Guided waves: The rectangular metal pipe waveguide. |